Ios 警报控制器内多个文本字段的空文本验证

这是我的ui警报控制器。如果任何文本字段为空，我需要禁用“提交”按钮。目前我有一个方法来验证一个文本字段，但我似乎不知道如何将其应用于所有文本字段。这是我的警报控制器和文本字段：

  let ac = UIAlertController(title: "Enter Custom Specifications", message: nil, preferredStyle: .alert)
    ac.addTextField { (textField : UITextField!) -> Void in
        textField.placeholder = "Material Name"
        textField.addTarget(self, action: #selector(self.textFieldDidChange(textField:)), for: .editingChanged)
    }

    ac.addTextField { (textField : UITextField!) -> Void in
        textField.placeholder = ""
        textField.keyboardType = UIKeyboardType.decimalPad
    }

    ac.addTextField { (textField : UITextField!) -> Void in
        textField.placeholder = ""
        textField.keyboardType = UIKeyboardType.decimalPad
    }

    ac.addTextField { (textField : UITextField!) -> Void in
        textField.placeholder = ""
        textField.keyboardType = UIKeyboardType.decimalPad
    }

使用上面第一个文本字段中调用的函数，我可以对每个文本字段进行正确的空字符串验证，这意味着当第一个文本字段为空时，提交被禁用，但当我开始键入时，提交被启用。如果我将函数调用放入每个textfield声明中，则每个声明都会出现相同的行为

 @objc func textFieldDidChange(textField: UITextField){
    if textField.text == "" {

        submitAction.isEnabled = false
    }
    else
    {
        submitAction.isEnabled = true

    }

}

我需要一种方法来检查所有文本字段在同一时间和提交禁用，如果其中任何一个是空的

编辑：

func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
    if textField.text == "" {
        //You can perfrom your activity here when textfield got blank or empty
        submitAction.isEnabled = false
    }
    else if textField.text != ""
    {
        submitAction.isEnabled = true
        //You can perfrom your activity here when textfield got not blank or not empty
    }
    //add your code here...
    return true
}

编辑2：

func textField（textField:UITextField，shouldChangeCharacters范围：NSRange，replacementString:string）->Bool{

    if let text = (textField.text as? NSString)?.replacingCharacters(in: range, with: string), !text.isEmpty {
        if let text = textField.text?.replacingCharacters(in: range, with: string), !text.isEmpty {
            submitAction.isEnabled = true
        } else {
            submitAction.isEnabled = false
        }
        return true
    }}

编辑3： 我可以在创建文本字段时将其命名为textfield“x”，而不是将所有文本字段都称为“textfield”：

ac.addTextField { (textField2 : UITextField!) -> Void in
        textField2.placeholder = "Column Width (in)"
        textField2.keyboardType = UIKeyboardType.decimalPad
        textField2.delegate = self
    }

我怎样才能让shouldChangeCharacters同时接受它们呢

编辑（解决方案）：

好的，我算出来了。PGDev在逻辑部分是正确的，但不是用于实际检查的委托函数。我要将他的答案标记为正确的，因为没有它，我不可能达到这一点

最初我们使用的是TextFieldDiEndediting，我认为它根本不起作用，因为一旦四个文本字段全部填充，它就无法重新启用submit按钮。我没有意识到的是，在调用TextFieldDiEndediting之后，我必须点击一个额外的textfield。这很有意义，因为它有“EndEditing”以我的名义

我使用了PGDevs逻辑并将其放入shouldChangeCharacters中，该语句工作正常但并不完美。我不确定它是否存在内部问题，但当您尝试填充最后一个文本框时，有时会将backspace（或其他内容）解释为一个字符，它会异常地抛出enable/！enable语句

textFieldDidChange使用PGDevs逻辑就是答案

设置要添加到警报控制器的文本框数量的类范围变量：

var textField1: UITextField?
var textField2: UITextField?
var textField3: UITextField?
var textField4: UITextField?

将此函数放在类函数的底部：

   @objc func textFieldDidChange(_ textField: UITextField) {

    let text1 = self.textField1?.text ?? ""
    let text2 = self.textField2?.text ?? ""
    let text3 = self.textField3?.text ?? ""
    let text4 = self.textField4?.text ?? ""

    if !text1.isEmpty && !text2.isEmpty && !text3.isEmpty && !text4.isEmpty {
        submitAction.isEnabled = true
    } else {
        submitAction.isEnabled = false
    }

}

 let ac = UIAlertController(title: "Enter Custom Specifications", message: nil, preferredStyle: .alert)
    ac.popoverPresentationController?.sourceView = self.view
    ac.addTextField { (textField : UITextField!) -> Void in
        textField.delegate = self
        textField.placeholder = "Material Name"
        self.textField1 = textField
        textField.addTarget(self, action: #selector(self.textFieldDidChange(_:)), for: .editingChanged)
    }

在警报控制器中生成实际文本字段时，调用上述函数：

   @objc func textFieldDidChange(_ textField: UITextField) {

    let text1 = self.textField1?.text ?? ""
    let text2 = self.textField2?.text ?? ""
    let text3 = self.textField3?.text ?? ""
    let text4 = self.textField4?.text ?? ""

    if !text1.isEmpty && !text2.isEmpty && !text3.isEmpty && !text4.isEmpty {
        submitAction.isEnabled = true
    } else {
        submitAction.isEnabled = false
    }

}

 let ac = UIAlertController(title: "Enter Custom Specifications", message: nil, preferredStyle: .alert)
    ac.popoverPresentationController?.sourceView = self.view
    ac.addTextField { (textField : UITextField!) -> Void in
        textField.delegate = self
        textField.placeholder = "Material Name"
        self.textField1 = textField
        textField.addTarget(self, action: #selector(self.textFieldDidChange(_:)), for: .editingChanged)
    }

---

这非常适合我。除非所有4行中至少有一个字符，否则提交将保持禁用状态。这可以用于任意多个文本字段。

尝试将每个文本字段的代理设置为显示警报的viewCobtroller，即

textField.delegate = self

使ViewController符合UITextFieldDelegate协议

class ViewController: UIViewController, UITextFieldDelegate {

实现相关的

UITextFieldDelegate

方法，例如：

func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
    if let text = (textField.text as? NSString)?.replacingCharacters(in: range, with: string), !text.isEmpty {
        submitAction.isEnabled = true
    } else {
        submitAction.isEnabled = false
    }
    return true
}

编辑：

您需要保留对所有

文本字段的
引用
，以便您可以检查所有字段中的
文本
，以
启用/禁用
提交
，即

var textField1: UITextField?
var textField2: UITextField?
var textField3: UITextField?
var textField4: UITextField?

let ac = UIAlertController(title: "Enter Custom Specifications", message: nil, preferredStyle: .alert)
ac.addTextField { (textField : UITextField!) -> Void in
    textField.delegate = self
    textField.placeholder = "Material Name"
    self.textField1 = textField
}
ac.addTextField { (textField : UITextField!) -> Void in
    textField.delegate = self
    textField.keyboardType = UIKeyboardType.decimalPad
    self.textField2 = textField
}
ac.addTextField { (textField : UITextField!) -> Void in
    textField.delegate = self
    textField.keyboardType = UIKeyboardType.decimalPad
    self.textField3 = textField
}
ac.addTextField { (textField : UITextField!) -> Void in
    textField.delegate = self
    textField.keyboardType = UIKeyboardType.decimalPad
    self.textField4 = textField
}

func textFieldDidEndEditing(_ textField: UITextField) {
    self.validate()
}


func validate() {
    let text1 = self.textField1?.text ?? ""
    let text2 = self.textField2?.text ?? ""
    let text3 = self.textField3?.text ?? ""
    let text4 = self.textField4?.text ?? ""

    if !text1.isEmpty && !text2.isEmpty && !text3.isEmpty && !text4.isEmpty {
        submitAction.isEnabled = true
    } else {
        submitAction.isEnabled = false
    }
}

在添加到
UIAlertController
时，设置每个
文本字段，即

var textField1: UITextField?
var textField2: UITextField?
var textField3: UITextField?
var textField4: UITextField?

let ac = UIAlertController(title: "Enter Custom Specifications", message: nil, preferredStyle: .alert)
ac.addTextField { (textField : UITextField!) -> Void in
    textField.delegate = self
    textField.placeholder = "Material Name"
    self.textField1 = textField
}
ac.addTextField { (textField : UITextField!) -> Void in
    textField.delegate = self
    textField.keyboardType = UIKeyboardType.decimalPad
    self.textField2 = textField
}
ac.addTextField { (textField : UITextField!) -> Void in
    textField.delegate = self
    textField.keyboardType = UIKeyboardType.decimalPad
    self.textField3 = textField
}
ac.addTextField { (textField : UITextField!) -> Void in
    textField.delegate = self
    textField.keyboardType = UIKeyboardType.decimalPad
    self.textField4 = textField
}

func textFieldDidEndEditing(_ textField: UITextField) {
    self.validate()
}


func validate() {
    let text1 = self.textField1?.text ?? ""
    let text2 = self.textField2?.text ?? ""
    let text3 = self.textField3?.text ?? ""
    let text4 = self.textField4?.text ?? ""

    if !text1.isEmpty && !text2.isEmpty && !text3.isEmpty && !text4.isEmpty {
        submitAction.isEnabled = true
    } else {
        submitAction.isEnabled = false
    }
}

每次在任何
文本字段中发生更改时调用
validate（）
，即

var textField1: UITextField?
var textField2: UITextField?
var textField3: UITextField?
var textField4: UITextField?

let ac = UIAlertController(title: "Enter Custom Specifications", message: nil, preferredStyle: .alert)
ac.addTextField { (textField : UITextField!) -> Void in
    textField.delegate = self
    textField.placeholder = "Material Name"
    self.textField1 = textField
}
ac.addTextField { (textField : UITextField!) -> Void in
    textField.delegate = self
    textField.keyboardType = UIKeyboardType.decimalPad
    self.textField2 = textField
}
ac.addTextField { (textField : UITextField!) -> Void in
    textField.delegate = self
    textField.keyboardType = UIKeyboardType.decimalPad
    self.textField3 = textField
}
ac.addTextField { (textField : UITextField!) -> Void in
    textField.delegate = self
    textField.keyboardType = UIKeyboardType.decimalPad
    self.textField4 = textField
}

func textFieldDidEndEditing(_ textField: UITextField) {
    self.validate()
}


func validate() {
    let text1 = self.textField1?.text ?? ""
    let text2 = self.textField2?.text ?? ""
    let text3 = self.textField3?.text ?? ""
    let text4 = self.textField4?.text ?? ""

    if !text1.isEmpty && !text2.isEmpty && !text3.isEmpty && !text4.isEmpty {
        submitAction.isEnabled = true
    } else {
        submitAction.isEnabled = false
    }
}

编辑了答案。您需要检查在
textField
textField中创建的最终字符串。
shouldChangeCharactersIn
方法中的text
在编辑前给出字符串。您使用的是哪个Swift版本？更新了代码。只需将其键入
NSString
。为方法
shouldchangeCharactere添加准确的代码rsIn
这样我就可以看一看了。只要将准确的代码和方法签名复制粘贴到您的文件中，看看您是否仍然面临这个问题，